JP7065191B2 - Wax composition and electrophotographic toner - Google Patents

Description

The present invention relates to a wax composition and an electrophotographic toner containing the wax composition.

More preferably, the present invention contains a wax composition and the wax composition which can impart low temperature fixability to the toner and can be suitably used for the toner having excellent dispersibility of the colorant contained in the toner. Regarding toner for electrophotographic photographs.

Toner used in electrophotographic equipment such as electrophotographic printers, facsimiles, and copiers having these functions includes colorants (carbon black, magnetic powder, etc.) in addition to the main component thermoplastic resin (binder resin). Pigments, etc.), charge control agents, waxes, and if necessary, fluidity additives, cleaning aids, transfer aids.

In the fixing step, the toner is heated by the fixing roll to be softened, and is fixed to the surface of the printing medium by receiving the pressure of the fixing roll to form an image. There are two actions of the toner wax contained in the toner, and one is the effect of improving the fixing characteristics. This is an anchor effect in which exudation occurs from a low temperature, and when the temperature is low, the adhesion to the recording paper is strongly maintained and the low temperature offset is prevented. The other is that the wax covers the surface of the fixing roller due to the exudation at high temperature, and the wax enters between the toner and the fixing roller, reducing the adhesive force between the toner and the fixing roller and preventing high temperature offset. It is a mold effect.

In recent years, the performance required for electrophotographic equipment such as printers, facsimiles, and copiers has become more sophisticated, and in addition to improving the equipment, the toner used in these equipment is also required to have higher functionality. Along with this, toner colorants and waxes are required to have good dispersibility in order to obtain high image quality. Further, it is desired that the fixing temperature is low, the offset resistance is excellent, and the fixing strength is excellent in order to speed up the rise and save the standby power.

Further, in a full-color image, generally, four kinds of toners of magenta, cyan, yellow and black are divided into a plurality of times and heated and melted on a transfer material to be transferred to form an image. The toner used here is required to have good meltability and color mixing property when heated, and therefore is required to have a low softening point and a low melt viscosity. In particular, color toner has a high concentration of colorant, and if the dispersibility is poor, the viscosity at the time of melting becomes high, the fluidity at the time of melting decreases, the peelability from the drum deteriorates, and the so-called offset property deteriorates. .. In addition, the color mixing property due to the melting of the superimposed toner deteriorates due to the decrease in fluidity at the time of melting.

Further, if the dispersibility of the colorant or wax is poor, the transparency is impaired. Therefore, in order to obtain a color image faithful to the original, a material having good dispersibility of the colorant or wax has been required.

Patent Document 1 discloses a method of using a natural wax such as carnauba wax or rice wax as a release agent as a method of exhibiting low-temperature fixability. When these waxes are used, low temperature fixability can be exhibited, but mold releasability may be insufficient and offset resistance may not be sufficiently exhibited. Further, these natural waxes had poor dispersibility of the colorant, and high-quality images could not be obtained.

Patent Document 2 describes a monoester having a specific complex viscosity. Although the monoester wax having a complex viscosity has good fixing properties, the ester wax obtained is remarkable because sulfuric acid is used as a catalyst when synthesizing the monoester wax and the reaction is carried out at a high temperature of 240 ° C. Coloring may occur, which may cause problems in terms of color reproducibility and colorant dispersibility during color printing.

Patent Document 3 discloses a toner using a mixture of carnauba wax and non-polar paraffin wax as a mold release agent.

According to this technology, a mixture of carnauba wax and non-polar paraffin wax is used as a mold release agent, cyclohexanedimethanol, which is a polyhydric alcohol component, is an essential component as a binder resin, and the acid value is 5 to 20 mgKOH / g. If so, it is possible to provide a color toner having good fixing property, glossiness, transparency, and releasability without applying fixing oil in the fixing device.

However, the non-polar paraffin wax has a problem that it is difficult to secure good dispersibility even if the acid value of the resin is increased as described above.

As described above, in the toner wax composition having low temperature fixability, there has been a demand for a toner wax composition having excellent dispersibility of the wax and the colorant. Further, there is a demand for toner that does not aggregate even under high temperature conditions. That is, there is a need for a wax composition for toner that can improve heat-resistant storage.
[Prior Art Document]
[Patent Document]

[Patent Document 1] Japanese Patent Application Laid-Open No. 4-362953 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-015673 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-287218

The problem to be solved

It is an object of the present invention to provide a wax composition for toner, which can impart heat-resistant storage property and low-temperature fixability to the toner, and is not affected by the chargeability of the resin and has excellent dispersibility of the colorant. And.

General disclosure

As a result of diligent studies to solve the above problems, the present inventors have combined a monoester wax (a) composed of a linear monocarboxylic acid and a linear monoalcohol with a specific ester (b). It has been found that by using the constructed composition as a wax for toner, the dispersibility of the colorant can be improved, and heat-resistant storage property and low-temperature fixability can be imparted.

That is, the present invention includes the following aspects:

<1> Wax (a) containing a monoester of a linear monocarboxylic acid and a linear monoalcohol, a linear monocarboxylic acid having one hydroxyl group and having 12 to 24 carbon atoms, and a linear chain having 12 to 24 carbon atoms. A wax composition for a toner containing an ester (b) of a mixed carboxylic acid composed of a monocarboxylic acid and glycerin. Here, the wax (a) containing a monoester of a linear monocarboxylic acid and a linear monoalcohol has a hydroxyl value of 30 or less.

<2> In the monoester of the linear monocarboxylic acid and the linear monoalcohol, the linear monocarboxylic acid has 20 to 24 carbon atoms and the linear monoalcohol has 22 to 38 carbon atoms. <1> The wax composition for toner according to.

<3> The wax composition for toner according to any one of <1> to <2>, which contains the wax (a) and the ester (b) in a mass ratio of 1: 4 to 4: 1.

<4> The wax composition for toner according to any one of <1> to <3>, wherein the hydroxyl value is 30 or more and the iodine value is 13 or less.

<5> The monoester of a linear monocarboxylic acid and a linear monoalcohol is described in any one of <1> to <4>, which is a monoester of a saturated linear monocarboxylic acid and a saturated linear monoalcohol. Wax composition for toner. Further, the mixed carboxylic acid may be a mixed carboxylic acid composed of a saturated linear monocarboxylic acid having 12 to 24 carbon atoms having one hydroxyl group and a saturated linear monocarboxylic acid having 12 to 24 carbon atoms.

<6> The wax composition according to any one of <1> to <5>, wherein the wax (a) contains 60% by weight or more of a linear monoester.

<7> An electrophotographic toner containing the toner wax composition according to any one of <1> to <6>.

<8> The electrophotographic toner according to <7>, wherein the added amount of the wax composition for toner is 2 to 20% by mass.

[The invention's effect]
By mixing the wax composition for toner of the present invention with toner, the dispersibility of the colorant contained in the toner is excellent, and excellent low temperature fixability and heat-resistant storage property can be imparted to the toner.

Hereinafter, embodiments of the present invention will be described.

The wax composition of the present invention comprises a wax (a) containing a monoester of a linear monocarboxylic acid and a linear monoalcohol, a linear monocarboxylic acid having one hydroxyl group and having 12 to 24 carbon atoms, and 12 to 12 carbon atoms. It contains a mixed carboxylic acid consisting of 24 linear monocarboxylic acids and an ester (b) with glycerin. Hereinafter, each component will be described.

[Wax (a)]
In the present invention, it is desirable that the wax (a) containing a monoester of a linear monocarboxylic acid and a linear monoalcohol has a hydroxyl value of 30 or less. The hydroxyl value of the wax (a) is derived not only from the hydroxyl group in the monoester but also from free alcohol, resin content and the like. Therefore, if the hydroxyl value exceeds 30, the heat resistance stability is lowered, and the chargeability is lowered, so that the image quality may be deteriorated. Further, when the hydroxyl value exceeds 30, the compatibility with the ester (b) becomes low, and even if the hydroxyl value of the wax composition is increased, only the wax (a) aggregates and the dispersibility decreases. Further, it is desirable that the monoester is a linear monoester having 42 or more carbon atoms. If the carbon chain has a branched structure, the compatibility with the binder resin contained in the toner is increased and the fixing release effect is reduced, so that it is necessary to use a linear monoester. Further, it is desirable that the wax (a) contains a linear saturated monoester as a monoester of the linear monocarboxylic acid and the linear monoalcohol. Due to the saturation of the monoester, it is less susceptible to oxidation and heat stability is improved. The wax (a) may contain a linear unsaturated monoester in place of / in addition to the linear saturated monoester.

The content of the linear monoester in the wax (a) is preferably 40% by mass or more, more preferably 60% by mass or more, and further preferably 80% by mass or more. The higher the content, the better the fixing and releasability, and the less the contamination due to the adhesion of the mold release agent to the paper ejection port. If it is less than 40% by mass, the fixing and releasability is inferior, and there is a possibility that contamination due to adhesion of the release agent to the paper ejection port may occur. The content of the linear monoester can be measured, for example, by gas chromatography.

Examples of the linear monoester used in the present invention include synthetic ester compounds and natural ester waxes.

The synthetic ester compound is obtained by an esterification reaction between a linear higher alcohol and a linear higher carboxylic acid or a linear higher carboxylic acid halide.

Examples of the linear higher alcohol include stearyl alcohol, arachidyl alcohol, behenyl alcohol, tetracosanol, hexacosanol, octacosanol, toriacontanol and the like.

Examples of the linear higher carboxylic acid include stearic acid, arachidic acid, behenic acid, lignoceric acid, cellotic acid, montanic acid, melissic acid and the like.

As a method for producing a synthetic ester compound, for example, first, an esterification reaction (condensation reaction) is carried out by using an excess of a linear higher carboxylic acid with respect to a linear higher alcohol component, and then an excess of the linear higher carboxylic acid is carried out. Is removed by deoxidation using an alkaline aqueous solution. A catalyst may be used in this reaction if necessary. Further, since the esterification reaction is an equilibrium reaction accompanied by dehydration, it is preferable to carry out the esterification reaction while distilling off water in the system. The reaction is carried out at a high temperature at which water in the system can be distilled off and the reaction raw materials do not escape from the system.

Natural ester wax is obtained by separating and purifying wax collected from animals and plants.

Examples thereof include candelilla wax, carnauba wax, rice wax, wood wax, jojoba oil, beeswax, lanolin wax, montan wax, sunflower wax and the like. However, since natural ester wax is a mixture of many kinds of compounds, it may be necessary to separate and purify it before use. Among these, rice wax and sunflower wax are preferable because they have a high monoester content of a saturated linear fatty acid having 20 to 24 carbon atoms and a saturated linear alcohol having 22 to 38 carbon atoms and have a hydroxyl value of 30 or less. The hydroxyl value is preferably 1 to 30, more preferably 1 to 20. Carnauba wax contains free alcohol and resin and has a high hydroxyl value of 35 or more. From this point of view, it is desirable that the wax (a) is something other than carnauba wax.

[Rice wax manufacturing method]
Rice wax is obtained by refining (refining) the crude wax produced as a by-product in the refining process of rice bran oil (rice crude oil) extracted from rice bran wax. The crude wax contains about 55 to 65% by mass of wax (ester wax), about 20 to 30% by mass of free fatty acid, and about 5 to 15% by mass of triglyceride. By removing the soft wax composed of free fatty acid and triglyceride in the crude wax, a fatty acid alcohol ester composed of a saturated linear monocarboxylic acid having about 22 to 24 carbon atoms and a saturated linear monoalcohol having about 24 to 38 carbon atoms can be obtained. Rice wax as the main component can be obtained. The main component indicates that the blending ratio of the saturated linear ester wax in the rice wax composition is high. For example, the content of the saturated linear ester in 100 parts by mass of the rice wax is 60 parts by mass or more and 99 parts by mass. Hereinafter, it can be said that it is 75 parts by mass or more and 98 parts by mass or less. Further, since rice wax has few polar substances such as resin, the hydroxyl value is 30 or less. As a method for removing soft wax composed of free fatty acids and triglycerides in crude wax, a method of obtaining by a recrystallization method using an organic solvent, a method of promoting esterification during purification, and a method of adding a polyhydric alcohol to rice wax are added. Low melting point triglycerides and aliphatic hydrocarbons of free fatty acids and impurities by repeating known rice wax purification methods such as esterification method and melting rice wax under heating and reduced pressure, and by combining purification methods. Can be obtained by removing and reducing. Further, by stirring a mixture of crude wax extracted from rice bran and ethanol under heating, colloidal particles containing wax and ethanol containing soft wax are separated, and then the wax is removed from the colloid-containing liquid. A purification method for recovering the contained colloidal particles can also be preferably applied.

[Ester (b)]
An ester of glycerin and a mixed carboxylic acid consisting of a linear monocarboxylic acid having 12 to 24 carbon atoms having one hydroxyl group and a linear monocarboxylic acid having 12 to 24 carbon atoms constituting the wax composition for toner of the present invention. In (b), the preparation method is not limited, and the above requirements may be satisfied. The linear monocarboxylic acid having 12 to 24 carbon atoms having one hydroxyl group may be a saturated linear monocarboxylic acid, and the linear monocarboxylic acid having 12 to 24 carbon atoms is also a saturated linear monocarboxylic acid. good. This makes the wax composition less susceptible to oxidation and improves heat stability. At least a part of the linear monocarboxylic acid constituting the ester (b) may be unsaturated.

As the ester (b), for example, an ester separated by curing, extracting, distilling, filtering, crystallization, column chromatography and other refining treatments of naturally occurring castor oil or the like is used alone or in combination. You may. Further, a method of synthesizing an ester using a single composition of carboxylic acid and glycerin as raw materials and then blending and preparing each ester so as to have the above-mentioned carboxylic acid composition, or a method of preparing the synthesized ester has the above-mentioned carboxylic acid composition. There is a method of preparing a monocarboxylic acid as a raw material in advance and then esterifying the acid to prepare the monocarboxylic acid. In the case of esterification, for example, a synthetic method by an oxidation reaction, a synthesis from a carboxylic acid and its derivative, a method using a dehydration condensation reaction from a carboxylic acid compound and an alcohol compound, and a reaction from an acid halide and an alcohol compound. , Production methods such as ester exchange reaction. A catalyst may be used in the reaction, and examples of the catalyst include acidic or alkaline catalysts such as zinc acetate and titanium compounds. When reacting, the reaction is carried out in the same amount of molar ratio of the raw material carboxylic acid and the raw material alcohol, or one component is excessively added and reacted. After that, purification may be performed by a recrystallization method, a distillation method, a solvent extraction method, or the like.

A linear monocarboxylic acid having one hydroxyl group and having 12 to 24 carbon atoms has a chemical formula of CH _3- [CH ₂ ] _x -CHOH- [CH ₂ ] _y -COOH.
(In the equation, x and y in the above equation are integers of 0 or more satisfying 9 ≦ x + y ≦ 21 (that is, x + y = (number of carbon atoms) -3).)
Examples thereof include hydroxymyristic acid, hydroxypalmitic acid, hydroxystearic acid, hydroxyarachidic acid, hydroxybehenic acid and the like, and among these, hydroxystearic acid having 18 carbon atoms is more suitable. preferable. The position of the hydroxyl group is not particularly limited, but 12-hydroxystearic acid having the hydroxyl group at the 12-position is preferable.

A linear monocarboxylic acid having 12 to 24 carbon atoms has a chemical formula of CH _3- [CH ₂ ] _z -COOH.
(In the formula, z in the above formula may be an integer satisfying 10 ≦ z ≦ 22 (that is, z = (number of carbon atoms) -2)), and may be represented by, for example, lauric acid. , Myristic acid, palmitic acid, stearic acid, araquinic acid, behenic acid, tetracosanoic acid and the like.

The carboxylic acid constituting the ester (b) is preferably composed of 60% by mass or more of a linear saturated monocarboxylic acid having 18 carbon atoms having a hydroxyl group, and more preferably in the range of 65 to 95% by mass. .. When the linear saturated monocarboxylic acid having 18 carbon atoms having a hydroxyl group is 60% by mass or more, the releasability of the toner is good, and winding and low temperature offset are less likely to occur in the printed image, which is preferable.

In the ester (b), when the number of carbon atoms constituting the skeleton of the linear monocarboxylic acid having a hydroxyl group and the linear monocarboxylic acid not containing a hydroxyl group is 12 or more, the toner is stored in a temperature environment of about 50 ° C. Even so, blocking of toner particles is unlikely to occur, and when the carbon number is 24 or less, the releasability of the toner is good, and wrapping and low temperature offset are less likely to occur in the printed image, which is preferable. Further, the linear monocarboxylic acid having a hydroxyl group and the linear monocarboxylic acid having 14 to 22 carbon atoms constituting the skeleton of the linear monocarboxylic acid not containing a hydroxyl group prevent the paper from being wrapped around the fixing roll in the printed image and at a low temperature. This is preferable because the effect of preventing offset is remarkable.

The acid value of the ester (b) is preferably 3 mgKOH / g or less, and more preferably 2 mgKOH / g or less. When the acid value is 3 mgKOH / g or less, it is preferable in terms of chargeability and stability during high-temperature storage.

[Wax composition]
The wax composition of the present invention comprises a wax (a) containing a monoester of a linear monocarboxylic acid and a linear monoalcohol, a linear monocarboxylic acid having 12 to 24 carbon atoms having one hydroxyl group, and 12 to 24 carbon atoms. The ester (b) of the mixed carboxylic acid composed of the linear monocarboxylic acid of No. 1 and glycerin is preferably a mass ratio of 1: 4 to 4: 1, more preferably 2: 3 to 3: 2. The content of the ester (b) of glycerin and a mixed carboxylic acid consisting of a linear monocarboxylic acid having 12 to 24 carbon atoms having one hydroxyl group and a linear monocarboxylic acid having 12 to 24 carbon atoms is equal to or higher than the above lower limit. Is preferable from the viewpoint of dispersibility and storage stability of the colorant. On the other hand, the content of the ester (b) of glycerin and a mixed carboxylic acid composed of a linear monocarboxylic acid having 12 to 24 carbon atoms having one hydroxyl group and a linear monocarboxylic acid having 12 to 24 carbon atoms is the upper limit. It is preferable that the value is equal to or less than the value from the viewpoint of releasability and volatile resistance.

The wax (a) containing a linear monocarboxylic acid and a monoester of a linear monoalcohol contains one or more of each, and the linear monocarboxylic acid and carbon having one hydroxyl group and having 12 to 24 carbon atoms. It can be blended with one or more of the ester (b) of glycerin and a mixed carboxylic acid consisting of a linear monocarboxylic acid having a number of 12 to 24.

As described above, the wax (a) containing the above-mentioned linear monocarboxylic acid and the monoester of the linear monoalcohol, the linear monocarboxylic acid having 12 to 24 carbon atoms having one hydroxyl group, and the direct chain having 12 to 24 carbon atoms. The wax composition obtained by mixing the mixed carboxylic acid composed of the chain monocarboxylic acid and the ester (b) with glycerin at a constant ratio as required is the wax and coloring in the toner composition. It is possible to improve the dispersibility of the agent. This mechanism can be considered as follows.

In the case of a single wax containing a monoester of a linear monocarboxylic acid and a linear monoalcohol, the polarity is low and the crystallinity is high. Therefore, when the wax is once melted and then solidified, only the wax aggregates and crystallizes. Therefore, the dispersibility of the wax may decrease and printing defects may occur. On the other hand, the ester (b) of a mixed carboxylic acid composed of a linear monocarboxylic acid having 12 to 24 carbon atoms having one hydroxyl group and a linear monocarboxylic acid having 12 to 24 carbon atoms and glycerin has a highly polar hydroxyl group. Therefore, it has a high affinity with the colorant and contributes to the dispersibility of the colorant in the binder resin, but the dispersibility of the wax is poor, and when it is blended alone with the toner, the dispersibility of the colorant is Although it is improved, poor shape removal and deterioration of storage stability may occur.

It consists of a wax (a) containing a monoester of a linear monocarboxylic acid and a linear monoalcohol, a linear monocarboxylic acid having 12 to 24 carbon atoms having one hydroxyl group, and a linear monocarboxylic acid having 12 to 24 carbon atoms. By combining the mixed carboxylic acid and the ester (b) with glycerin, the crystallinity, crystallization behavior, and polarity of the wax containing the monoester of the linear monocarboxylic acid and the linear monoalcohol can be changed directly. A linear monocarboxylic acid having 12 to 24 carbon atoms having one hydroxyl group and a linear monocarboxylic acid having one hydroxyl group and having a single hydroxyl group while significantly improving dispersibility due to aggregation and crystallization of the wax alone containing a chain monocarboxylic acid and a monoester of a linear monoalcohol. Ester (b) alone with a mixed carboxylic acid consisting of a linear monocarboxylic acid having 12 to 24 carbon atoms and glycerin can greatly improve the poor shape removal and deterioration of storage stability, and can be used for waxes and colorants in the toner composition. It is presumed that the dispersibility will be improved. Since the ester (b) has a hydroxyl group in the molecule, unlike the wax (a), even if a large number of hydroxyl groups are present, the heat stability is not impaired by free alcohol or the like. Rather, the hydroxyl group of the ester (b) contributes to the improvement of the dispersibility of the wax composition and the like.

In the endothermic curve measured by a differential scanning calorimeter (DSC), the wax composition of the present invention preferably has a peak top temperature of 60 ° C. or higher and 100 ° C. or lower, more preferably 70 ° C. or higher and 90 ° C. or higher. It is below ° C. When the peak top temperature of the wax composition used in the present invention is at least the above lower limit temperature, the crystallinity in the toner is not lowered, and the storage stability and the developability are not deteriorated, which is preferable. Further, when it is equal to or lower than the upper limit temperature, the fixing temperature of the toner does not increase, which is preferable.

The wax composition of the present invention comprises a wax (a) containing a monoester of a linear monocarboxylic acid and a linear monoalcohol, a linear monocarboxylic acid having 12 to 24 carbon atoms having one hydroxyl group, and 12 to 24 carbon atoms. The ester (b) of the mixed carboxylic acid composed of the linear monocarboxylic acid of No. 1 and glycerin preferably has a hydroxyl value of 30 or more and an iodine value of 13 or less.

If the hydroxyl value of the wax composition is too low, the polarity is low and the affinity for the colorant is low, so that the dispersibility of the colorant in the binder resin is lowered and printing defects may occur. , 30 mgKOH / g or more and 160 mgKOH / g or less are preferable. Further, when the iodine value of the wax composition is too high, the wax is aggregated by itself and the dispersibility is lowered, and wrapping and low temperature offset are likely to occur in the printed image. Therefore, 13 or less is desirable. The lower limit of the iodine value is usually 0.01 mg. Further, the wax composition preferably has an acid value of 10 mgKOH / g or less. When the acid value is 10 mgKOH / g or more, the polarity is lowered and the dispersibility may be deteriorated. Therefore, the acid value is preferably 10 mgKOH / g or less, and the toner containing the wax composition of the present invention is contained. The chargeability becomes even better. The lower limit of the acid value of the wax (a) is usually 0.01 mgKOH / g.

Here, the iodine value of the wax composition is a value measured by a method based on JOCS 2.3.4.1-2013 of the "2003 Standard Oil and Fat Analysis Test Method" of the Japan Oil Chemists' Society. Similarly, the acid value can be measured according to JOCS 2.3.1-2013. The hydroxyl value of the wax composition and the wax (a) can be measured according to JOCS 2.3.6.2-2013.

[Manufacturing method of wax composition]
The wax composition of the present invention can be produced by a known method. For example, after producing a wax (a) containing a monoester of a linear monocarboxylic acid and a linear monoalcohol, a linear monocarboxylic acid having one hydroxyl group and having 12 to 24 carbon atoms and a linear chain having 12 to 24 carbon atoms can be produced. It may be produced by blending an ester (b) of a mixed carboxylic acid composed of a monocarboxylic acid and glycerin, and further blending a binder resin or the like described later.

It consists of a wax (a) containing a monoester of a linear monocarboxylic acid and a linear monoalcohol, a linear monocarboxylic acid having 12 to 24 carbon atoms having one hydroxyl group, and a linear monocarboxylic acid having 12 to 24 carbon atoms. From the viewpoint of quality variation, it is preferable to heat the ester (b) of the mixed carboxylic acid and glycerin to a temperature equal to or higher than the melting point, mix them uniformly, and then perform filtration, cooling, atomization, and the like.

The wax composition of the present invention thus obtained can impart low-temperature fixability to the toner and can achieve high image quality by satisfactorily dispersing the colorant. Therefore, the present invention can be suitably used as a wax composition for toner.

The wax composition of the present invention is blended with a binder resin (also referred to as a binder resin), a colorant, a charge control agent, and the like, and a toner is produced by a usual production method. The blending amount (addition amount) of the wax composition for toner of the present invention in the toner is usually 1 to 20 parts by mass, preferably 2 to 20 parts by mass, and more preferably 8 parts by mass with respect to 100 parts by weight of the entire toner. It is about 20 parts by mass, particularly preferably 12 to 20 parts by mass. When the lower limit value is within the above range, the heat-resistant storage property of the toner is satisfactorily exhibited, and when the upper limit value is within the above range, the low temperature fixability of the toner can be satisfactorily exhibited. Since the wax composition of the present invention has excellent dispersibility in the toner, it can exist in the toner without becoming lumpy even if the addition amount is increased. In the toner, the wax composition for toner of the present invention is blended alone or in combination of two or more. The method for confirming whether or not the toner contains the wax composition is not particularly limited, and for example, a method of stirring the toner with an organic solvent in which the wax component in the toner is selectively dissolved may be used. When the extract obtained by stirring is dried, a white solid substance (wax) is obtained in the residue.

The extract is measured using, for example, an infrared spectrophotometer (FT-IR), (differential scanning calorimetry (DSC), pyrolysis (GC / MS)), and various waxes and esters (b). The structures of the wax (a) and the ester (b) can be specified by comparing with the standard peak of the hydroxyl group. Further, the peak of the higher alcohol constituting the ester of the wax (a) and the ester (b). The mass ratio of the wax (a) and the ester (b) can be calculated by quantitatively analyzing the peak of the carboxylic acid having a hydroxyl group constituting the above.

Specific examples of the binder resin, the colorant, and the charge control agent are as follows, and known materials can be appropriately used.

(Bundling resin)
Examples of the binder resin include polyester-based resins, styrene- (meth) acrylic acid-based copolymer resins, thermoplastic elastomers, styrene-based resins, (meth) acrylic acid-based resins, and olefin-based resins (for example, polyethylene and polypropylene). α-olefin resin, etc.), vinyl resin (for example, polyvinyl chloride, polyvinylidene chloride, etc.), polyamide resin, polyether resin, urethane resin, epoxy resin, polyphenylene oxide resin, terpenephenol resin, poly Examples thereof include lactic acid resin, hydrogenated rosin, cyclized rubber, cycloolefin copolymer resin and the like. These can be used alone or in combination of two or more. Among these, polyester-based resins and styrene- (meth) acrylic acid-based copolymer resins are preferable from the viewpoint of being able to satisfy the requirements such as image quality characteristics, durability, and productivity of toner in a well-balanced manner.

(Colorant)
The colorant may be a black pigment, a magenta pigment, a cyan pigment, a yellow pigment, or a pigment of another color. Black pigments include carbon blacks such as lamp black, thermal black, acetylene black, channel black and furnace black, and niglosin dyes, and magenta pigments include rose bengal, dupon oil red, and C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 163, 202, 206, 207, 209; C.I. I. Pigment Violet 19; C.I. I. Violet 1, 2, 10, 13, 15, 23, 29, 35 and the like are aniline blue, calco oil blue, ultramarine blue, methylene blue chloroid, phthalocyanine blue, C.I. I. Pigment Blue 2, 3, 15, 16, 17; C.I. I. Bat Blue 6; C.I. I. Acid blue 45 and the like are used as yellow pigments such as chrome yellow, quinoline yellow, and C.I. I. Pigment Yellow-1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 65, 73, 74, 83, 93, 97, 128, 155. , 180 are used alone or in admixture. Magenta is a preferred colorant for full color because of its good color mixing and excellent color reproducibility. I. Pigment Red 57, 122, Cyan is C.I. I. Pigment Blue 15 and Yellow are C.I. I. Pigment Yellow 17, 93, 155, 180.

(Charge control agent)
Examples of the positive charge control agent include modified products of niglocin and fatty acid metal salts; and quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammoniumtetrafluoroborate. Diorganosin oxide such as dibutyltin oxide, dioctyltinoxide, dicyclohexyltinoxide; Diorganotinborate such as dibutyltinborate, dioctyltinborate, dicyclohexyltinborate; pyridium salt, azine, triphenylmethane compound, cationic functional group Examples thereof include low molecular weight polymers having the above. These positive charge control agents may be used alone or in combination of two or more. Among these positive charge control agents, niglocin-based compounds and quaternary ammonium salts are preferably used. Examples of the negative charge control agent include organic metal compounds such as acetylacetone metal complexes, monoazo metal complexes, naphthoic acid or salicylic acid-based metal complexes or salts, chelate compounds, and low molecular weight polymers having anionic functional groups. Can be mentioned.

These negatively charged charge control agents can be used alone or in combination of two or more. Among these negatively charged charge control agents, salicylic acid-based metal complexes and monoazo metal complexes are preferably used. The content of the charge control agent is usually in the range of 0.1 to 5.0 parts by weight, preferably 0.5 to 3.0 parts by weight, based on 100 parts by weight of the binder resin.

The present invention will be described in more detail below by showing a production example of the wax composition for toner of the present invention and an evaluation method thereof.

[Wax composition for toner]
Wax compositions for toner (C-1) to (C-5) and a wax composition for comparison were prepared according to the formulations shown below, and the dispersibility of the colorant of the obtained wax composition is shown in Table 1. rice field. In addition, (C-1) to (C-5) correspond to Examples 1 to 5.

[Preparation of Wax Composition for Toner (C-1)]
480 g of rice wax (linear monoester content 90%) and 120 g of hardened castor oil in a four-necked flask equipped with a thermometer, nitrogen introduction tube, stirring blade and cooling tube [(a): (b) = 4: 1] The sample was collected, heated and melted at 100 ° C. under nitrogen, and heated and stirred for 30 minutes so that the contents became uniform. This mixture was allowed to cool at room temperature and solidified to obtain a wax composition (C-1). The hydroxyl value of rice wax was 8.

The content of the linear monoester was measured by using a gas chromatography device (GC-2025 manufactured by Shimadzu Science Co., Ltd.) and a column (DB-1HT manufactured by Azilent Co., Ltd.) under vaporization chamber conditions of 380 ° C. and 150 ° C. to 370 ° C. Gas chromatography measurement was performed by raising the temperature to ° C. (5 ° C./min) and holding for 10 minutes, and calculating the ratio of the peak area of the linear monoester to the total peak area. The following C-2 to C-4 and D-1 to D-5 were also measured by the same method.

[Wax composition for toner (C-2)]
Toner wax composition (C-2) in the same manner as in (C-1) except that the mass ratio of rice wax: cured castor oil was adjusted to 1: 1 [(a): (b) = 1: 1]. ) Was obtained. The hydroxyl value of rice wax in the wax composition was 8.

[Wax composition for toner (C-3)]
Toner wax composition (C-3) in the same manner as in (C-1) except that the mass ratio of rice wax: cured castor oil was adjusted to 1: 4 [(a): (b) = 1: 4]. ) Was obtained. The hydroxyl value of rice wax in the wax composition was 8.

[Wax composition for toner (C-4)]
A toner wax composition (C-4) was obtained in the same manner as in (C-2) except that a rice wax having a hydroxyl value of 25 and a linear monoester content of 78% was used.

[Wax composition for Comparative Examples 1 to 5]
A toner wax composition was obtained in the same manner as in (C-1) except for the following changes in the toner wax compositions (D-1 to D-5). Note that (D-1) to (D-5) correspond to Comparative Examples 1 to 5.
[Preparation of wax composition (D-1)]
In (D-1), polyethylene wax (Mitsui High Wax 320P manufactured by Mitsui Chemicals, Inc.) was used instead of the cured castor oil of (C-1). The hydroxyl value of rice wax in the wax composition was 8.

[Preparation of wax composition (D-2)]
In (D-2), rice wax alone was used without using hardened castor oil. The hydroxyl value of rice wax in the wax composition was 8.

[Preparation of wax composition (D-3)]
In (D-3), a monocarboxylic acid alone was used instead of the cured castor oil of (C-3). The hydroxyl value of rice wax in the wax composition was 8.

[Preparation of wax composition (D-4)]
In (D-4), rice wax was not used, but hardened castor oil alone was used. ..

[Preparation of wax composition (D-5)]
In (D-5), carnauba wax was used instead of the rice wax of (C-2). The hydroxyl value of the ester wax in the wax composition was 38.

[Evaluation method of wax composition]
The acid value, iodine value, and hydroxyl value of the wax compositions of (C-1) to (C-5) and (D-1) to (D-5) were evaluated by the following methods.
(1) Acid value of wax composition; JOCS (Japan Overseas Christian Medical Cooperative Association) 2.3.1-2013.

(2) Iodine value of wax composition; JOCS (Japan Overseas Christian Medical Cooperative Society) 2.3.1-2013.

(3) Hydroxyl value of wax composition and wax (a); JOCS (Japan Overseas Christian Medical Cooperative Association) 2.3.6.2-2013 was compliant.

(4) Thermal Properties of Wax Compositions The thermal properties of the wax compositions of (C-1) to (C-4) and (D-1) to (D-5) were evaluated. "DSC-50" manufactured by Shimadzu Science Co., Ltd. was used for measuring the thermal properties of the wax composition. The measurement was carried out by placing about 20 mg of the wax compositions C-1 to C-3 and D-1 to D-3 in aluminum sample holders, using alumina as a reference material, and under a nitrogen atmosphere (200 ml / min). ), The thermal characteristics were confirmed when the temperature was raised from normal temperature ° C to 120 ° C at 5 ° C / min, cooled again to 0 ° C at −5 ° C / min, and then raised again to 120 ° C at 5 ° C / min. The results are shown in Tables 2 and 3 described later.

[Evaluation of colorant dispersibility using wax composition]
[Example 1]
In Example 1, the wax composition according to (C-1) was sufficiently stirred and mixed with a resin (polyester, colorant (pigment red), charge adjuster (low molecular weight polymer having a cationic functional group) and the like, respectively, with a mixer. After that, it was heated and kneaded at a temperature of 130 to 140 ° C. with a twin-screw melt-extruded kneader. The kneaded product was evaluated for its dispersed state. Fine pulverization was performed and classification was performed to obtain toners of each hue. The addition amount (content) of the wax composition in the toner was set to 10% by mass.

In addition, a part of the kneaded mixture was cross-sectionally observed using an optical microscope to evaluate the dispersibility of the colorant and the release agent. Specifically, the dispersibility of the colorant and wax is as follows: ○ if the domain diameter of the largest mass of the colorant is less than 3 μm, Δ if it is 3 μm or more and less than 6 μm, and × if it is 6 μm or more. evaluated. The dispersibility of the release agent was evaluated as ◯ if it was less than 5 μm by measuring the domain diameter of the largest mass of the colorant, Δ if it was 5 μm or more and less than 10 μm, and × if it was 10 μm or more.
◯: The colorant particles are uniformly dispersed without agglomeration.
Δ: Slight aggregation is observed.
X: Aggregates and voids are observed.

[Heat-resistant storage]
The degree of cohesion of the toner containing the wax composition according to Examples and Comparative Examples was measured by the following method, and the heat-resistant storage property of the toner was evaluated. Specifically, 20 g of toner was put into a plastic container having a capacity of 200 mL, and allowed to stand in a constant temperature and humidity chamber (“PH-3KT” manufactured by Espec Co., Ltd.) set at 50 ° C. for 48 hours before being taken out. Next, three types of sieves having an opening of 150 μm, an opening of 75 μm, and an opening of 45 μm were attached to a powder tester (PT-S manufactured by Hosokawa Micron Co., Ltd.) in this order. 2 g of toner for heat-resistant storage evaluation was put on a sieve having an opening of 150 μm. Toner for heat-resistant storage evaluation was sieved under the condition of Leostad scale 2 and time of 10 seconds. The mass of toner remaining on the sieve was measured. From the measured toner mass, the toner cohesion degree (mass%) was calculated according to the following formula. Toners having a degree of cohesion of less than 20% by mass were evaluated as having good heat-resistant storage stability.

Cohesion (% by mass) = a + b + c
a = (Weight of residual toner on a sieve with an opening of 150 μm / 2) × 100
b = (weight of residual toner on a sieve with an opening of 75 μm / 2) × 100 × (3/5)
c = (weight of residual toner on a sieve with an opening of 45 μm / 2) × 100 × (1/5)

[Low temperature fixability]
Using the toners obtained in Examples and Comparative Examples as measurement targets, the set temperature of the heat fixing roll of a commercially available copying machine (trade name; EP-870Z manufactured by Minolta Co., Ltd.) was set to 120 ° C., and transfer with an unfixed image was performed. The toner image of the paper was fixed. Then, the formed fixing image was rubbed with a cotton pad, and the fixing strength was calculated by the following formula and used as an index of low energy fixing property.
Fixing strength = (Image density of fixing image after rubbing / Image density of fixing image before rubbing) × 100 (%) Fixing strength is 80% or more, 70% or more and less than 80%, 60% or more and less than 70% When it was less than 60%, the low temperature fixability was evaluated as ⊚, ◯, Δ, and ×, respectively.

[Examples 2 to 5]
Toner was obtained by the same method as in Example 1 except that the wax compositions according to (C-2) to (C-4) were used instead of (C-1). However, in Example 5, a styrene-acrylic acid-based copolymer was used instead of polyester. In Examples 2 to 5, the dispersibility, heat-resistant storage property, and low-temperature fixability were evaluated in the same manner as in Example 1.

[Comparative Examples 1 to 5]
Toner was obtained by the same method as in Example 1 except that the wax compositions according to (D-1) to (D-5) were used instead of (C-1). In Comparative Examples 1 to 5, the dispersibility, heat-resistant storage property, and low-temperature fixability were evaluated in the same manner as in Example 1. The evaluation results of Examples 1 to 5 and Comparative Examples 1 to 5 are shown in Table 1.

As shown in Table 1, the wax compositions (C-1) to (C-4) of Examples 1 to 5 all have a low acid value and a high hydroxyl value, so that they have a highly polar hydroxyl group and a colorant. The affinity of the colorant was increased, and the dispersibility of the colorant was good.

Tables 2 and 3 show endothermic curves of the wax compositions (C-1) to (C-4) and (D-1) to (D-5) by a differential scanning calorimeter (DSC). From the results in Table 2, good dispersibility was shown by lowering the crystallinity of the wax, and the endothermic peak was in the range of 60 to 100 ° C., and the result was excellent in low temperature fixability. When these compositions are used as a wax for toner, the colorant is highly dispersed in the binder resin, which can contribute to high image quality.

From Tables 1 to 3, Comparative Examples 1 and 2 have a remarkably low acid value, an endothermic peak is sharp, and when the wax is once melted and then solidified, only the wax aggregates and crystallizes, and the dispersibility of the wax and the dispersibility of the wax The result was that the dispersibility of the colorant was low. Further, in Comparative Example 3, since the hydroxyl value is low but the acid value is high, the polarity is high and the dispersibility is good, but the heat-resistant storage property is inferior. In Comparative Example 4, since the cured castor oil alone was used without containing rice wax, the dispersibility of the wax deteriorated. In Comparative Example 5, carnauba wax was used instead of rice wax. Since carnauba wax has a low content of linear monoester and also contains a large amount of resin and the like, the dispersibility was inferior even if the hydroxyl value in the wax composition was close to that of Example 4.

From the results of Tables 1 to 3, it can be seen that the toner of the present invention has good dispersibility of the colorant, good low-temperature fixability, excellent heat-resistant storage property, and good printing characteristics.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a wax having excellent dispersibility of a colorant, high transparency, high-quality image characteristics, and excellent heat-resistant storage property, and a toner using the wax.

Claims (6)

Wax (a) containing a monoester of a saturated linear monocarboxylic acid and a saturated linear monoalcohol, a saturated linear monocarboxylic acid having 12 to 24 carbon atoms having one hydroxyl group, and a saturated direct chain having 12 to 24 carbon atoms. It contains an ester (b) of a mixed carboxylic acid consisting of a chain monocarboxylic acid and glycerin.
The wax (a) containing a monoester of a saturated linear monocarboxylic acid and a saturated linear monoalcohol has a hydroxyl value of 30 or less and contains 80% by weight or more of the linear monoester.
Wax composition. In the monoester of the saturated linear monocarboxylic acid and the saturated linear monoalcohol,
The saturated linear monocarboxylic acid has 20 to 24 carbon atoms, and the saturated linear monoalcohol has 22 to 38 carbon atoms.
The wax composition according to claim 1. The wax composition according to claim 1 or 2, which contains the wax (a) and the ester (b) in a mass ratio of 1: 4 to 4: 1. The wax composition according to any one of claims 1 to 3, wherein the hydroxyl value is 30 or more and the iodine value is 13 or less. An electrophotographic toner containing the wax composition according to any one of claims 1 to 4 . The electrophotographic toner according to claim 5 , wherein the addition amount of the wax composition is 2 to 20% by mass.